Electric door-motor



Dec 29, 193E. v R. J. PARSSONS 1,338,959

ELECTRIC DOOR MOTOR Filed Aug. 1'7, 1926 avwemvoc ROBERT J. PARSONSPatented Dec. 29, 1931 UNITED STATES MENTS, TO CONSOLIDATED CAR-HEATIN ACOBIORATIONOF NEW YORK PATENT OFFICE I ROBERT .1. lmmsons, orscimnnc'rany, NEW YORK, ASSIGNOR, IBY MEsNE Assum- G COMPANY, INC., OFALBANY, YORK,

Erncra rc noon-Moron Application filed August 17, 1926. Serial at.129,829.

For a detailed description of the present form of my invention,reference may be had to the following specification and to the accompanying drawings forming a part thereof, wherein Fig. 1 is a planpartly in section of my device;

Fig. 2 is a front view of the switch box with the cover removed and Fig.3 is a diagram of the circuits.

My invention relates to electric door operators wherein an electricmotor is arranged to reciprocate acar-door, or any door requiringsimilar movement.

Referring to Fig. 1 E represents an electric motor having its casingconnected to a gear-box J and a switch-box F. p The armature shaft ofthe motor carries a spur-pinion which drives a gear-wheel 21 on theshaft of which is a second pinion 22 that drives a gear-wheel 23, and onthe shaft of said gearwheel 23 is a third pinionv 24 that drivesgearwheel 25 on the door-arm shaft D. The doorarm is shown at G and, inamanner now well known and requiring no illustration, oper ates the doorback and forth by a movement over an arc of approximately 180 degrees, aroller on the outer end of the arm engaging a vertical guideway on therear edge'of the door. The door-arm shaft D enters the switch-box F and,as appears in Fig. 2, carries two cams H and K which, for convenience ofillustration, are shown separately in the figure, one above the other,although it is to be understood that in practice the two cams are placedside by side on the common shaft D, each acting on its individual set ofswitches. The cam H acts alternately on the levers P and Q while cam Kacts alternately on the levers S and R. The lever Q, operates thespring-pressed switch that opens and closes the connection betweencontacts 11 and 12, while lever P operates the similar switch Y whichopens and closes-the connection between'contacts 13 and 14 The cam H isshown in its midway position both switches being open. In a similar waythe cam K controls the closure; of the connections between contacts 9and 10 of switch V on the one hand and contacts 15 and 16 of switch W onthe other hand. 1

The cam H is longer in a circumferential direction than cam K, and,therefore, as it moves to one side or the other, will operate switch Xor Y before cam K operates switch V or W. i

In operation we may assume that the motor is propelling the door towardsits closed position and shaft D with cams H and K is rotating in ananti-clockwise direction, havin reference to Fig. 2. As the door approaces the closed position the first effect will be the closing of switch Xby the action of cam H on lever Q. The result of this may be seenby'reference to the circuit diagram of Fig. 3. This assumed door-closingdirection of the motor movement has been estab lishedby moving themanual control-switch A to the left, thereby connecting contacts 1 and5, also contacts 2 and 6 of that switch, while the contacts 9 and 10 ofswitch V (which is the door-closing limit switch) are as yet unopened.Thereby the current will pass from trolley T, to contacts 6 and 2, tocontacts 10 and 9, to field-magnet A of the motor, to motor armature Cand to ground. The field-magnet coil A is so wound as to give the motorits desired door-closing direcdoor-opening current of that coilnamely,in a direction to cause a co-operation of fieldmagnet coils A- and B toclose the door), thence to contacts 5 and 1 of the controlswitch, tocontacts 12 and 11, now closed, of switch X, and to ground. By theaforesaid closure of switch X three effects are. roduced: (1) the cooerative connection a oresaid of field-coils and B, (2) the voltageapplied to armature C is reduced (3) the voltage applied to field-coil Ais increased. As a result the motor speed is reduced, but the motortorque is maintained, or even in creased. The reduction in motor speedis due to the stronger field magnet and the re duced voltage applied toits armaturenot to a weakening of its torque. Thereby the motor isenabled to complete the run of the door wbecause of its maintainedtorque, although its-speed is reduced preparatory to its stopping.Consequently the motor slows down as it approaches the end of its run,and the inertia of its high-speed armature, which has such alargegearing ratio with respect to the comparatively slow-moving door, isbrought under control initially prior tothe actuation of thelimit-switch. Following the operation of switch X, as just described, bythe cam H, comes the operation of limitswitch Vby cam'K and lever S.That interrupts the flow of current from'trolley T totheimotor coils,but there-still remains a closedcircuit for the motor armature O,fromground on one side of it,'through the armature itselfpand thence throughfield-coil B, control-switch contacts 5 and 1, contacts 12 and "11 ofswitch X and back to ground. This puts a final brake-effect on the motorwhich nowacts as a short-circuited generator and brings it'to rest. Theaction is the same for the opposite direction of movement of the doorandmotor, theswitches Y and V being then operatedin succession with'thesameeffect as the aforesaid switches X and V. In each case the motor isfirst automatically weakened .and itslimit-switch then opened ina'way-togive abraking'effect to bring it mechanically to a stop.

.It willbe noted that while field-magnet coil 3B,.when acting alone,willhave an effect which is the'reverse of the corresponding coil A whenacting alone, yet when switch X is closed,"as'above described, bothcoils will be energized to give the same direction of rotation and willtherefore supplement each other. The two coils when thussupplementingeach other will double the effect of A or B when actingalone. In addition, the drop in-voltage thereby-applied to the armaturewill increase somewhat'the VOlAlfIQ applied to coil A because the-linevoltage remains unchanged. Therefore the field-magnet effect is more.than doubled when'the two fieldn1agnet coils thus supplement each other.After the aforesaid closure of switch X, which inaugurates the firstslowing-down stage or period, the limit switch V is opened and therebyithe current supply is cut off. This inaugurates the secondslowing-down stage or period. The motor then beginsto actas a generatorandthe stopping effect of that action isamaintaine'd until the door andmotor stop. WVhileI do not now know of any motor other than a door motorwith its door ,qea red thereto that would call for my braking orstopping device, yet it will be understood. that the door shaftmentioned in the following claims includes any equivalent shaftrequiring the same operative treatment as the shaft D of my abovedescribed apparatus.

lVhat I claim as new and desire to secure by Letters Patent is:

1. The combination with a door shaft, of a. driving motor connectedthereto and stopping therewith, said motor including an. armature andoppositely wound tiel d magnets so that the motor may be operated ineither direction, a supply circuit for said motor, a normally closedlimit switchcontrolling said circuit and one of said field magnets,means for opening said switch at a predetermii'ied time during theoperation of said door shaft, a normally open'field magnet switch, meansfor operating the field magnet switch in advance ofthe operation of-saidlimit switch, and means associated withsaid field magnet switch forconnecting said field magnets in series with each other so to reduce thevoltage supply to said armature.

The combination with a door shaft, of a driving motor conccted theretoand stopping therewith, said motor including an armature and two fieldmagnet coils connected respectively for opposite directions of armaturerotation, a supply circuit for said motor, and an automatic controllerfor said motor comprising twoscts of switches, each set including alimit switch for controlling the motor circuit and one of said fieldmagnet coils, means for operating said switch to open the motor supplycircuit at a predetermined time during the operation of'said door shaft,:1 field magnet switch acting in advance of said limit switch, and meansassociated with said limit switch to connect the inactive field magnetcoil tothe supply and to reduce the voltage supplied to said armature.

3. The combination with door shaft, of a driving motor connected theretoandstopping therewith, said motor including an armatureand oppositelywound field 1nagnets so'that the motormay be operated in eitherdirection, a. supply circuit for said motor, a manual reversing switchfor said motor, and an automatic controller in series with said manualswitch,'said controller in cluding a normally closed limit switchcontrolling said circuit and one of said field marrnets, means foropening said switch at a predetermined time'during'the operation of thedoor shaft, a normally open field magnet switch, means for operating thefield magnet switch in advance of the operation of said limit switch,and meansassociatcd with said field magnet switch for conecting theinactive field magnet coil to the motor supply circuit and to reduce thevoltage supplied to said armature.

4t. The combination with a door shaft, of a driving motor connectedthereto and stopping therewith, said motor including an armature and.two field magnet coils arranged for opposite directions of armaturerotation, a supply circuit for said motor, a manual reversing switch,and an automatic controller including a limit switch controlling saidmotor circuit and one of said field magnets, a field magnet switch,means associated with said field magnet switch for connecting theinactive field magnet coil to said motor supply circuit so as to reducethe voltage supply on said armature, and cams mounted on said shaft andpositioned to engage and operate the respective switches, the cam foroperating said field magnet switch being positioned to actuate the samein advance of the operation of said limit switch.

The combination with a door shaft, of a driving motor connected theretoand stopping therewith, said motor including an armature and oppositelywound field magnets so that the motor may be operated in eitherdirection, a supply circuit for said motor, a manual switch having twosets of contacts, means associated with one set of contacts forselectively connecting said circuit to the ground or through one of saidfield magnets and the armature, said means including a normally closedlimit switch, and means for automatically opening said switch at apredetermined time during the operation of said shaft, means associatedwith the other set of contacts for connecting the last mentioned fieldmagnet to ground'through the other field magnet, said means including anormally open switch, and means for automatically closing the lastmentioned switch in advance of the opening of said limit switch so as toreduce the voltage supplied to said armature.

6. The combination with an electric motor having two field magnetsarranged for opposite directions of motor rotation, and an armaturehaving a terminal connection with both coils at a position intermediatebetween them, a limit switch normally biased to circuit closed positionand controlling the circuit through one of said coils, a groundconnection around said armature and including the other coil, avoltageswitch controlling the ground connection, said voltage switch beingnormally biased to open circuit position, a control switch provided withcontacts for establishing circuit to the motor through the limit switchand through the voltage switch respectively, a shaft rotatably actuatedby said motor and having cams, and means interposed between said camsand said switches for efl'ecting operation of the switches duringrotation of said shaft, said cams being positioned to operate theswitches in a predetermined sequence.

Signed at Albany, county of Albany, State of New York, this 6th day ofAug, 1926.

ROBERT J PARSONS.

